Adding all kinds of embedded lists:
.cm-hmd-list-indent .cm-tab,
ul ul,
ol ul,
ul ol,
ol ol {
position: relative;
}
.cm-hmd-list-indent .cm-tab::before,
ul ul::before,
ol ul::before,
ul ol::before,
ol ol::before {
content:'';
border-left: 1px solid var(--background-modifier-border);
position: absolute;
}
.cm-hmd-list-indent .cm-tab::before { left: 0; top: -5px; bottom: -4px; }
ul ul::before,
ol ul::before,
ul ol::before,
ol ol::before {
left: -11px;
top: 0;
bottom: 0;
}